Genetic diversity of Procambarus clarkii populations based on mitochondrial DNA and microsatellite markers in different areas of Guangxi, China.

The red swamp crayfish (Procambarus clarkii) is a famous invasive species. However, it has become one of the most important freshwater aquaculture resources in China. Herein, we focus on five artificial cultured populations of P. clarkii in Guangxi, southern China to investigate the genetic diversity based on mitochondrial DNA and microsatellites. The results revealed that the genetic diversity of P. clarkii populations in southern Guangxi (NN and DT) was lower than in central (LZ and LB) and northern (RS) Guangxi. A total of 17 haplotypes were captured from 100 individuals and haplotype 2 mainly existed, and the number of haplotype in NN and DT was less than other populations. The AMOVA showed that genetic variation was determined by within populations. The observed mismatch distribution of overall populations fit the expected distributions, indicating that no obvious demographic expansion, but unimodal was observed in RS, LZ and LB. Fst among most of groups exhibited moderate differentiation. Nevertheless, the gene flow demonstrated there had extensive gene exchanges between different populations, particularly between LZ and LB. UPGMA tree revealed that NN and DT belonged to the same clade, whereas the remaining populations were in the other clade. According to the genetic diversity, there is a need to improve the germplasm resources of P. clarkii in southern Guangxi.